31 December 2008

Neal Stephenson's Anathem. I was a little wary after The Baroque Cycle, but I really enjoyed this— it was a real page-turner. Stephenson has created such a rich and lush world for this novel that you just don't want it to end. And there are dozens of fascinating ideas scattered throughout the story.

World of Goo (WiiWare; $15). "If I had played this game as a kid I might be a civil engineer now." World of Goo is an addictive physics-based puzzle game. You connect elastic "goo balls" to build structures to reach a goal while avoiding various obstacles. It's not as easy as it sounds because the structures sag under their own weight. The game physics are astoundingly realistic—so when your tower of goo balls collapses, you get the sense that it was your own darned fault. However, the levels are really well-designed and many of them require these critical epiphanies. The interesting thing about World of Goo is that it is surprisingly deep. As you play more and more, you hone your intuition for the game physics. So after you reach the primary goal in each level, you can come back later and play it again for the "OCD" point, which requires you to reach the goal in an even more efficient manner. World of Goo was written by, like, three guys in a garage, and yet it is very polished. Highly recommended.

I'm in the middle of Brian Greene's The Fabric of the Cosmos. Greene has a gift for developing accessible (and faithful) analogies that expose the core ideas—but not the math—behind physical phenomena, such as relativity and quantum mechanics. Highly recommended for laypeople.

21 December 2008

Replicating one of the most controversial behavioral experiments in history, a Santa Clara University psychologist has found that people will follow orders from an authority figure to administer what they believe are painful electric shocks.

Additionally, the volunteers confronted a novel situation—having never before been in such a setting, they had no idea of how they were supposed to act, he said.

Finally, they had been told that they should not feel responsible for inflicting pain; rather, the "instructor" was accountable. "Lack of feeling responsible can lead people to act in ways that they might otherwise not, said Burger.

"When we see people acting out of character, the first thing we should ask is: 'What's going on in this situation?'"

Milgram's assessment of his own experiment seems no less true today:

Ordinary people, simply doing their jobs, and without any particular hostility on their part, can become agents in a terrible destructive process. Moreover, even when the destructive effects of their work become patently clear, and they are asked to carry out actions incompatible with fundamental standards of morality, relatively few people have the resources needed to resist authority.

19 December 2008

Paul Krugman argues that the nonsensical accounting and compensation systems in the financial "services" industry allowed money managers to keep reaping big bonuses even as their clients lost everything. He suggests that the primary difference between Bernard Madoff and his colleagues was that

...while Mr. Madoff was apparently a self-conscious fraud, many people on Wall Street believed their own hype.

Well, shame on us for entrusting our money to people who were not actually held accountable and to a totally opaque system that allowed the managers to spin their numbers however they wanted. Not a winning plan.

But the really tragic part, in my view—the part where our losses may not be so easily computed—is the that the growth of the financial services industry produced a distorted view of what is really valuable:

[How] much has our nation's future been damaged by the magnetic pull of quick personal wealth, which for years has drawn many of our best and brightest young people into investment banking, at the expense of science, public service and just about everything else?

The root problem (people copying your card) still exists for physical magstripe cards, though. This is a huge advantage that RFID has over magstripe and I wonder why people haven't made a bigger deal out of it. Once you've read the magstripe off a card, you have all that there is to know about the card. But an RFID chip can contain active machinery inside. It's a black box that you can only interact with in certain ways, unless you reverse-engineer the hardware to figure out what the silicon is doing (this is not super easy). So you can implement a challenge-response mechanism which resists some kinds of man-in-the-middle attacks (remember the hubbub about fake ATMs?).

04 December 2008

Given n "objects" in n-dimensional space, it is possible to divide all of them in half in volume with a single (n - 1)-dimensional hyperplane.

The theorem gets its name because in the case n = 3, it implies that if I have a ham sandwich consisting of arbitrarily shaped pieces of ham, cheese, and bread (hah!), and an obsessive-compulsive friend, I can cut the sandwich in half with one swipe so that each of us gets exactly half the ham, half the cheese, and half the bread.

22 November 2008

The New York Times published a feature about the Netflix challenge and some of the people who are racking their brains working on it. One major problem to surmount is, apparently, the film "Napoleon Dynamite":

The reason, Bertoni says, is that "Napoleon Dynamite" is very weird and very polarizing. [...] It’s the type of quirky entertainment that tends to be either loved or despised. The movie has been rated more than two million times in the Netflix database, and the ratings are disproportionately one or five stars. [...]

Amazingly, Bertoni has deduced that this single movie is causing 15 percent of his remaining error rate [...] if Bertoni could anticipate whether you’d like "Napoleon Dynamite" as accurately as he can for other movies, this feat alone would bring him 15 percent of the way to winning the $1 million prize.

08 November 2008

I think Thomas Friedman has his finger on the reason why I, and probably more than few others, voted the way we did this year. The election was not about McCain and Obama or their foreign policies or even their economic policies. It was about repudiating the Bush administration:

[They] knew that after the abysmal performance of the Bush team, there had to be consequences for the Republican Party. Electing McCain now would have, in some way, meant rewarding incompetence. It would have made a mockery of accountability in government and unleashed a wave of cynicism in America that would have been deeply corrosive.

It's the reason I would have voted for San Francisco's Measure R. The name "George W. Bush" must be widely discredited for all posterity, that policies like his may be avoided in the future.

Not a completely rational reason to vote, but so little about politics is rational anyway.

02 November 2008

While doing some research I ran across the AHA's booklet of Heart and Stroke Facts. It is easy to read and gives a very good overview for laypeople of many of the things which can go wrong with your heart and circulatory system (including both "plumbing" and "electrical" issues), as well as some of the things which are done to fix those things.

22 October 2008

When asked by Jim Lehrer why he became an economist, Paul Krugman replied:

[There's] a very old series by Isaac Asimov—the Foundation novels—in which the social scientists who understand the true dynamics save civilization. That's what I wanted to be; it doesn't exist, but economics is as close as you can get, so as a teenager I really got into it.

Indeed, economics is the closest thing we have to what I'd call "people engineering": studying or designing systems (institutions) with people as their components and identifying principles, mathematical in nature, that govern their behavior. It is humbling that this works and astonishing that it works well.

I recently heard Brian Greene (The Elegant Universe and The Fabric of the Cosmos) speak about his new book, Icarus at the Edge of Time. Unlike his previous books, this one is ("intentionally", he says) a work of fiction. It is also one of those cardboard books, and is 16 pages long.

This switch in genre is somewhat surprising. Professor Greene noted that many people who might never pick up one of his other books might pick up, and read, this one. They might even learn something: the plot of the story hinges on one detail of general relativity(!). This is impressive, really. It brings a narrative to this field of science where narrative is so rarely seen, and it makes a small piece of the subject accessible to laypeople. I know something about the "real" science behind this, and I do believe it is beautiful, but I'd be the first to admit that a narrative is appealing in a more visceral kind of way.

I think many advocates for science and technology could take a page (har, har) from Professor Greene. It's so easy to get lost in the details of what we do that we forget that, for better or for worse, people respond to stories much more effectively than they respond to even the most logical arguments.

17 October 2008

In the second installment of The Future of Driving, Timothy Lee explains how self-driving cars may someday transform society. When cars can drive themselves, we will of course be able to do actually enjoyable or productive things while our cars are driving us around. But the higher-order effects are much more interesting...

For starters, self-driving cars means renting car service (what you would call a taxi for, nowadays) will become cheaper and easier because you don't have to pay for a human driver. This will change the economics of buying vs. renting a car and the latter will become quite attractive for people who don't need 100% of a car. More renting of cars means better utilization of each car: the car that drove you to work today can drive away and take other people places all day. Better utilization of cars means much less space in cities needed for parking lots. Moreover, what parking space we do need will be used much more efficiently when intelligent cars can park very densely (park each other in, etc.) and automatically move out of the way when asked to.

This is really fascinating business. Read the article to find out why Lee thinks self-driving cars will change not only city planning, but the design of cars, and retail/commerce.

Terence Tao posted about small sampling and polls, and the somewhat non-intuitive fact that the margin of error of a poll only depends on the size of the sample and not at all on the size of the population being sampled; even if the latter quantity is quite small (e.g. 1,000 polled out of a population of 200,000,000) the margin of error may be quite good. An analogy:

Suppose one is in front of a large body of water (e.g. a sea or ocean), and wants to determine whether it is a freshwater or saltwater body. This can be done very easily: dip one’s finger into the body of water and taste a single drop. This gives an extremely accurate result, even though the relative proportion of the sample size to the population size is, literally, a drop in the ocean; the quintillions of water molecules and salt molecules present in that drop are more than sufficient to give a good reading of the salinity of the water body.

Alternatively: it's easy to see that for polling purposes the only relevant parameter of a population is its average opinion (in particular, its size is not relevant). If all you have is a phone that connects you to a random person in a population when you pick it up, then it is impossible to tell whether the population consists of a billion people evenly split between candidates A and B, or a thousand people evenly split between candidates A and B, or even whether the population consists of one person who flips a coin to decide whether to say A or B every time you call him.

Voting protocols

Ron Rivest spoke on security in voting systems at a GBC-ACM function. There have been a couple of voting protocols proposed recently (Scantegrity II and Twin voting) which allow the integrity of an election to be independently verified by all (end-to-end verifiability), while simultaneously preventing any voter from proving how she voted. Importantly, software is only used for auxiliary purposes in these protocols and we need not trust the software at all. End-to-end verifiability would lend confidence to election results in a way which is simply impossible in current systems, and in a democracy we should demand no less than this degree of transparency.

15 October 2008

There are 1011 stars in the galaxy. That used to be a huge number. But
it's only a hundred billion. It's less than the national deficit! We used
to call them astronomical numbers. Now we should call them economical
numbers.

22 September 2008

Douglas Diamond and Anil Kashyap, two colleagues of Steven Levitt, have graciously written this FAQ on the Lehman and AIG implosions. It explains, for laypeople, the significance and causes of the financial intervention we've seen in the past weeks.

18 September 2008

Scott Adams, of Dilbert fame, commissioned a survey of 500 economists in which he asked them about their opinions on how the presidential candidates would do in several categories. The results may, or may not, surprise you.

Thanks, Scott Adams, for giving economists some street cred by (gasp) soliciting their opinions! Economic thinking is really valuable, even if economics is no exact science, and even if most people think that economists just do... well, they don't even know, but they think it must be unimaginably boring.

12 September 2008

My intuition for how to cook chicken is gradually becoming more and more developed. But there are still surprises (in this case, a good one), like this astonishingly tasty dish we made last week.

Last week I received some Arnabal sweet smoked chili oil which I got off a wine.woot sale. I prepared the recipe below using chili oil instead of EVOO. This chili oil, which is not like the typical Chinese chili oil, gives a delicious smoky (but not overpoweringly spicy) flavor. Somewhat surprisingly, this actually goes great with the curry.

We ate it with broken rice, which I bought a bag of because it was the only thing left at the store. It has this fantastic nutty flavor and a different texture from normal rice. It is almost habit-forming. Whenever I prepare anything with rice now, the rice always tries to steal the show.

Takeaway messages from this blog post: go buy a case of chili oil and a bag of broken rice.

Curry chicken

Ingredients: chicken breasts, flour, curry powder, salt, pepper

Slice the chicken breasts to get thinner pieces (I usually slice each into two or three pieces). This is critical for even cooking.

Mix flour, salt, pepper, and curry powder to taste in a bowl. Coat the chicken with the flour mixture.

27 August 2008

For this holiday season, most of the major computer manufacturers will have some sort of netbook offering. This really represents a sea change in the way computers are made and marketed, and I think we have the OLPC's precedent to thank for it.

Technology is constantly getting cheaper, but manufacturers have always offset the savings by adding more features. As recently as 2005, it would have been folly to think that the manufacturers would abandon this (very profitable) collusion. The idea that a small computer could be less expensive instead of more expensive had not even entered the public mind. Yes, you could buy a "subnotebook" but it would have cost you about $2500.

OLPC's plans really shook things up. They said they wanted to bring computers to the developing world, a market which the industry was doing little for at the time. You could tell that everyone wanted a piece of the action. And that was why there was such vitriol in OLPC's interactions with Intel and Microsoft. But more significantly, I think, people started to understand that an inexpensive computer was something you would have to engineer, instead of just being something you picked up out of the trash and repurposed. That was the spark for the XO-1 and the Eee PC. Competition being as awesome as it is, now everyone wants a piece of the netbook pie.

Intel and Microsoft are somewhat apprehensive about this, and quite understandably.

Microsoft has grudgingly continued to ship Windows XP: for most of these computers, for reasons of both cost and performance, it's either Windows XP or GNU/Linux. In order to keep from cannibalizing sales of (the more expensive) Windows Vista, Microsoft enforces a bunch of crazy restrictions about the maximum specifications of computers that they'll sell you Windows XP for at the lowest prices. I don't see this ad-hoc business ending well. And if GNU/Linux gets a lot of mainstream credibility by making inroads on netbooks, that credibility will spread to the desktop (desktops and full-size notebooks), and people will think carefully when they have to decide whether to plop down another $50 or whatnot to get Windows.

Intel has already launched a lower-margin line of chips (Atom) to meet netbook demands. But, its continued relevance is far from certain. Many netbooks are designed to run GNU/Linux because Windows is either cost-prohibitive, or too slow, or vendors want to differentiate with their software. When the OS consists almost entirely of free software which the vendor can recompile at the drop of a hat, it can be made to run pretty much identically on another architecture. Just contrast that to Windows, where people have been stalling on moving from x86 to x86-64 for ages now. A bunch of non-x86 phones and handhelds already run Firefox, GTK apps, the whole shebang. How long is it before we see ARM processor-based netbooks?

05 August 2008

In the wake of the [bus decapitation and cannibalism] attack, Greyhound has scrapped a billboard ad campaign that extolled the relaxing upside of bus travel which had the unfortunate punch line stating: "There's a reason you've never heard of 'bus rage'".

04 August 2008

The Wall Street Journal reports on Dig This, a so-called "heavy equipment playground". It's a 10-acre lot with an excavator, a bulldozer, and other machinery that you can pay to play with.

Hoisting, digging and razing costs $280 to $650, depending on the machine and the number of hours spent aboard. Even at those prices, Mr. Mumm doesn't expect to turn a profit for at least another year — he's had about 90 paying customers so far. But he feels confident that he's tapped into an underserved corner of the American psyche.

His customers have ranged from corporate chief executives to an 84-year-old woman. Many find it tough to say why it's such a thrill to play with rocks. "I'm giggly when you ask about it," says Hank Edwards, a recent customer.

Their instructors will train you to use the equipment and give you hints via a two-way radio. And the following sounds like an awesome idea:

He's even dreaming about creating a save-your-marriage course, with a licensed counselor coaching couples through exercises that require good communication.

05 July 2008

[The] difficulty of creating a character increases with each new major character that is added to the tale. Characters, as most writers understand, are truly developed through their relationships with others. If there are only two significant characters, then there is only one relationship to be explored. If there are three characters, however, there are four relationships: Between A and B, between B and C, between C and A, and finally the relationship when all three are together.

Even this does not begin to explain the complexity—for in real life, at least, most people change, at least subtly, when they are with different people...

I have seen this time and time again with my friends, with other family members. Our whole demeanor changes, our mannerisms, our figures of speech, when we move from one context to another. Listen to someone you know when they pick up the telephone. We have special voices for different people; our attitudes, our moods change depending on whom we are with.

So when a storyteller has to create three characters, each different relationship requires that each character in it must be transformed, however subtly, depending on how the relationship is shaping his or her present identity. Thus, in a three-character story, a storyteller who wishes to convince us of the reality of these characters really has to come up with a dozen different personas, four for each of them.

04 July 2008

What better way to celebrate our nation's birthday than by setting off 10 tons of explosives?

I went to Boston's Esplanade and had a gorgeous view of the fireworks. They manage to outdo themselves every year. Highlights: pastel color fireworks, fireworks that explode in cube shapes and in smiley faces, fireworks attached to parachutes (or balloons, I couldn't tell), the biggest shells I have ever seen, and explosions that feel like a kick in the chest.

The 1812 Overture with live ordnance is also something that has to be experienced.

I picked up a copy of the New York Times yesterday, and they had printed a facsimile of the Declaration of Independence full page on the back of one section. I read it and it moved me to tears. It is one of those things that makes you feel good, not just about this country, but about humanity. Thanks, NYT.

28 June 2008

Revealing Errors brought attention to "medireview" and "clbuttic", two instances where automated systems were known to silently make substitutions for certain words in e-mails or other documents. (These attempts were figured out because the software was quite ineptly designed, often making substitutions for offensive strings like "ass" even when they were not surrounded by word boundaries, thereby creating many nonsensical words.)

This sort of technique is often used to prevent XSS attacks or to substitute offensive words with innocuous ones. But there may be much subtler applications of this technique with more nefarious motives. One could imagine that this could be used for censorship, and to shape or interfere with certain kinds of discourse.

The fact that these sorts of techniques are now known to be widespread (even if they are not generally malicious) might encourage more people to digitally sign their email with programs like GPG.

24 June 2008

Two Bits: The Cultural Significance of Free Software, by Christopher Kelty, is an anthropological study of the people behind free software. Kelty sets out to answer (among others) some questions about free software: first, what are the defining components and conventions of a free software community? What are the characteristics of software (and of the geeks that create it) that have made free software so powerful and seemingly eternal? Naturally, this can help us better understand other fields which are trying to adopt some of the principles of freedom and openness (education, biology, music and film, to name a few) and figure out how they can better reach their own goals.

The Future of the Internet (And How to Stop It), by Jonathan Zittrain, examines the latest generation of electronic devices that interact with the internet (typified by the iPhone) and laments that their locked-down nature threatens the cycles of innovation that made the internet— and those devices— possible in the first place.

Happily, both of these books are available for download and remixing under Creative Commons licenses (Attribution Non-commercial Share-alike 3.0). When I saw him at MIT, Kelty remarked that he could not in good conscience write a book about freedom and free software and then not make that book free. But it is also fortunate that this freedom allows these books to reach the widest possible audience. Naturally, if you read either of these books online and enjoy them, I would encourage you to buy a paper copy.

12 June 2008

I made this change to my /etc/hosts a few weeks ago and have not looked back since.

The only side effect I've observed is that I now go to Google News about once an hour, but that is probably less than I used to check Reddit, and Google News does not have anywhere near the addictive qualities of Reddit.

07 June 2008

You want more fuel-efficient cars? Don't regulate. Don't mandate. Don't scold. Don't appeal to the better angels of our nature. Do one thing: Hike the cost of gas until you find the price point.

Unfortunately, instead of hiking the price ourselves by means of a gasoline tax that could be instantly refunded to the American people in the form of lower payroll taxes, we let the Saudis, Venezuelans, Russians and Iranians do the taxing for us -- and pocket the money that the tax would have recycled back to the American worker.

A gas tax won't happen, but gas prices are more effective at spurring changes in the auto industry than any government regulations ever could:

[Last December's new fuel efficiency standards] involved, as always, dozens of regulations, loopholes and throws at a dartboard. And we already knew from past history what the fleet average number does. When oil is cheap and everybody wants a gas guzzler, fuel efficiency standards force manufacturers to make cars that nobody wants to buy. When gas prices go through the roof, this agent of inefficiency becomes an utter redundancy.

At $4 a gallon, the fleet composition is changing spontaneously and overnight, not over the 13 years mandated by Congress. (Even Stalin had the modesty to restrict himself to five-year plans.) Just Tuesday, GM announced that it would shutter four SUV and truck plants, add a third shift to its compact and midsize sedan plants in Ohio and Michigan, and green light for 2010 the Chevy Volt, an electric hybrid.

29 May 2008

Microsoft and Intel's much-feared "Trusted Computing" initiative seems to not have gotten off the ground, but smaller-scale efforts have become much more common in the last few years. Manufacturers can now regulate after-market behavior with chips and cryptography, which can create much more specific and onerous burdens than the old tools: licenses, contracts, and mechanical design. These restrictions are making their way into music, videos, phones, printers, cars, you name it.

In a 2002 New York Times column, economist Hal Varian argued that these techniques cause prices to go up in uncompetitive markets. But, more insidiously, they stifle innovation, as demonstrated by the following example (among others). In an effort to make more money selling ink cartridge, some printer manufactuerers have added chips to ink cartridges preventing operation if the cartridge has been refilled by a third party.

A hot area of computer-chip research design involves taking off-the-shelf inkjet printers, loading the cartridges with magnetic ink and squirting integrated circuits onto metalized plastic. That technology may revolutionize integrated circuit production — but it definitely requires using products in ways the manufacturer didn't intend.

[...]

That sort of thing will be simply impossible if digital rights management becomes commonplace.

These measures create many roadblocks for experimentation. The real shame is that by doing so they make innovation a lot less attractive for all but the most powerful people and organizations, those who can pay their way around such restrictions before even starting. Total control of inventions by their manufacturers may be the death knell for the legend of the inventor in the garage.

I just finished
reading Banker
to the Poor by Muhammad Yunus. He tells the story of how he founded
Grameen Bank (roughly translated, "village bank"), which makes small loans to
the poor without requiring collateral. (This is known as microcredit
and loans are typically less than USD $100.) As a result of loans from
Grameen Bank and similar organizations in other countries, tens of millions
of families have escaped poverty for good.

In Yunus's native country of Bangladesh, many poor people were virtually in
a state of slavery because, just in order to acquire raw materials for their
craft or seeds for planting, they were forced to take out loans at shockingly
high interest rates. The moneylenders effectly captured all the profit,
making it impossible for the borrowers to escape poverty. Grameen Bank has
empowered its borrowers by lending them just enough to allow them to break
out of this cycle. In fact, most borrowers are women who had previously been
entrusted with little or no financial responsibility. Borrowers quickly
become financially self-sufficient; most are able to expand their
enterprises, taking out larger and larger loans each year.

Part of Grameen's signature is that it requires prospective borrowers to
form small groups. Group members help each other stay focused and provide
insurance when calamity strikes.

Grameen Bank's success has been remarkable. The repayment rate tops
98%. The poor are so desperate, Yunus says, that given this one chance to
pull themselves up, they are just not going to let it slip away.

The mindset behind this program runs completely counter to prevailing wisdom
in the United States. In the US, we assume that to make poor people
self-sufficient we need to give them training or an education, so that they
can get a wage-paying job. Meanwhile, anyone who starts a venture needs huge
amounts of capital, enough that we need to keep them on a leash by telling
them how to run their business. So it is, to me, unsurprising that Grameen
Bank's idea— providing small loans and advising, but not managing,
borrowers— started not in the US but in a country like Bangladesh,
where most people are self-employed. But the success of microcredit even in
prosperous nations such as the US shows that the entrepreneurial spirit is
common, and not just in Bangladesh.

Banker to the Poor is not just the story of Grameen Bank but also a
critique of mainstream economic thinking and institutions. Yunus objects that
even though the standard economic axioms promise certain kinds of global maxima, the
objectives that are maximized are deeply flawed. Why should we consider
increases in total production or wealth to be important if it is entirely
possible (or indeed, common) that most of the prosperity is seen by the
richest few? According to Yunus, it is this misguided focus that has
distracted us from the things that could actually help us eliminate
poverty.

Yunus believes that with self-sustaining institutions like Grameen Bank
which are chartered to help the poor, we could relegate poverty to the
history books. Coming from most people, this would be idealistic fluff. But
on the strength of Grameen Bank's success, I am ready to take Yunus's word
for it.

Yunus tells a great story, and I am well on my way into his next
book, Creating a World Without Poverty.

11 May 2008

Speed Racer may very well give your brain diabetes, and I state that as compliment.

The plot is pretty predictable (evil megalomaniac with henchmen, unlikely alliance of good guys, various plot twists) but fairly well done, and the characters are enjoyable to watch.

The visuals, however, are stunning. From the studio logos all the way through the closing credits, Speed Racer contains contains gratuitous amounts of color and motion. It's gripping and fluid and, yes, beautiful. The Wachowskis have apparently figured out exactly how to turn on the pleasure centers in human brains, which is pretty remarkable. What more could you ask for from a movie?

25 April 2008

During the Go Tournament in Paris, staged between 22 and 24 March 2008 by the French Go Federation (FFG), the MoGo artificial intelligence engine developed by INRIA running on a Bull NovaScale supercomputer, won a 9x9 game of Go against professional 5th DAN Catalin Taranu. This was the first ever officially sanctioned 'non blitz' victory of a 'machine' over a Go Master.

(Taranu came back to win the match 2-1.) For a long time it was thought that computers would never be able to defeat skilled humans at Go because the staggering number of possible Go positions (much more than are possible in chess) demands human pattern-matching skills.

MoGo, like many top Go programs today, makes use of Monte Carlo (randomized) methods in order to tackle the inherent complexity of the problem.

22 April 2008

Super Mario Galaxy. Unlike Zelda: Twilight Princess, it's easy to play even if you have under half an hour. The controls feel great and the music is truly memorable. Gameplay is so satisfying that I frequently go back and replay levels for fun.

09 April 2008

The courses being cut — Italian, Latin literature, French literature and computer science AB — are among the least popular in the AP portfolio. Italian, introduced three years ago, has attracted 1,642 students and 305 teachers nationwide, one-fifth the number who expressed interest before it was created, AP officials said. Courses in French and Latin literature serve 2,068 and 3,771 students, respectively. The most popular AP subjects, including U.S. history and English literature, reach hundreds of thousands of students each year.

The Post didn't report numbers for APCS, but if something like 4000 students take it, then about one in 200 of those students goes to SHS. Incroyable.

In 2005, Congress granted to the DHS the power to void any federal law that might interfere with building a border fence. And then...

Last week, Mr. Chertoff issued waivers suspending more than 30 laws he said could interfere with "the expeditious construction of barriers" in Arizona, California, New Mexico and Texas. The list included laws protecting the environment, endangered species, migratory birds, the bald eagle, antiquities, farms, deserts, forests, Native American graves and religious freedom.

This reads like an article out of The Onion.

Congress also (probably unconstitutionally) exempts any such decisions from review by the courts.

06 April 2008

The group of Magicicada known as Brood XIV is coming out in Massachusetts and other parts of the Northeast this year in April or May. According to Wikipedia, they will be seen in parts of Ohio, Kentucky, Tennessee, Massachusetts, Maryland, North Carolina, Pennsylvania, Virginia, West Virginia, New York, and New Jersey.

The last time I remember cicadas being in the news was the emergence of Brood X in 2004.

Magicicada come in varieties that come out (to mate) once only every 13 or 17 years. They are divided into 30 broods based on what year they come out. Broods I-XVII are 17-year cicadas and XVIII-XXX are 13-year cicadas.

Scientists theorize that having a life cycle that is a large prime number of years long helps the cicadas to escape predators or parasites. Predators that come out every year would alternately have to lie low for 16 years and be completely overwhelmed by cicadas on the 17th. And predators with any period of between 2 and 16 years would have to wait 17 cycles (34 to 272 years), because 17 is relatively prime to all numbers between 2 and 16. Either way, not a great niche to be in if you're a predator. (The same numerical reason prevents 13- and 17-year cicadas from interbreeding too much and creating intermediate forms.)

Hypothesis: for Pinewood Derby cars, air drag is irrelevant; most slowdown is due to rolling resistance and the wheels bumping up against the track as the car wobbles.

Strategy: cut grooves into the axles to reduce the axle-wheel contact area, and grease the axles up well. To reduce wobbling, increase the angular momentum (around a vertical axis) by placing weights at the very front and very back of the car.

Validation: Cliff's car placed second one year and an improved design placed first, showing up a bunch of cars that looked like drag racers and that had been tested in wind tunnels.

28 March 2008

When I have an important but short task hanging over my head, I will often neglect it and other less important tasks, and waste time on the internet instead.

It is strange in that, in the absence of the first task, I would generally have been happy to work on the other tasks rather than waste time. This is not only obviously suboptimal for my productivity, it probably also violates some basic criterion of economic rationality.

22 March 2008

Keith Devlin recently published in his
MAA column an essay by Paul Lockhart
titled A
Mathematician's Lament, a critique of American primary school
mathematics education. It's a fascinating read, and the quickest 25 pages
I've read lately.

Marvin Minsky has written an
essay, What
makes Mathematics hard to learn? In it he suggests some ideas for
teaching math effectively, and relates a couple of poignant anecdotes about
math education, my favorite of which is this one:

...that child [who had been struggling with learning to
multiply] had a larger-scale complaint: "Last year I had to learn the
addition table and it was really boring. This year I have to learn another,
harder one, and I figure if I learn it then next year there will be another
one and there'll never be any end to this stupid nonsense." This child
imagined 'math' to be a continuous string of mechanical tasks— an
unending prospect of practice and drill. It was hard to convince him that
there would not be any more tables in subsequent years.

These got me thinking about my mathematics education. Perhaps the single
most lasting skill I've picked up from doing math is learning how to prove
things: not those two-column geometry proofs that everyone is tired of, but
really knowing how to put together a line of argument that is both easy to
follow and watertight. And there is not just one way to do that. Like
writing, there is both art and science in it: choosing terminology and
metaphors carefully; designing the structure and scaffolding of an argument;
putting in enough details, but not too many; being economical with words.

Moreover, from mathematics I picked up an inclination to ask why things are
true. In math— unlike in any natural science— you can always get
down to the bottom of things by asking "Why?" until you get back to the
axioms. Frankly, that's an amazing idea.

Yet, I saw very little of the "art of proof" and the "mathematician's
skepticism" until I started going to
a math circle in high school.
Most of my public school math classes focused on learning recipes rather than
talking about the why. When we learned, say, the quadratic formula,
we did the derivation (based on completing the square) in class. But that
derivation was soon squirreled away so we could do "applications", which is a
fancy name for plugging numbers in ad nauseum. Personally, I find this
tragic: the trouble is that in mathematics, the process is far
more important and interesting than the result. More pragmatically, a student
who remembers the idea of completing the square can derive the quadratic
formula (and more) anytime, but students are given little incentive to think
about, or remember, that beautiful idea. Most students will forget the
quadratic formula once they have stopped using it for a few years, and if
their experience with mathematics is that it is just a bunch of facts, they
are more than likely never going to get that quadratic formula back.

The result of these methods, as Lockhart notes, is that pretty much no one
today knows what mathematics is (not even math teachers). And students are
being led to think that they dislike math when they actually just dislike
whatever it is that they're being taught in math classes. Doing math is a
deeply creative and enlightening process, but those aspects of mathematics
are very rarely seen by the general public.

11 March 2008

Kenneth R. French has circulated a working paper titled "The Cost of Active Investing" summarizing an analysis in which he tried to quantify the costs of investors trying to beat the market. The price tag is huge: over $100 billion in 2007 alone. This represents money those investors would have saved had they simply bought an index fund.

One [implication] is that a typical investor can increase his annual return by just shifting to an index fund and eliminating the expenses involved in trying to beat the market. Professor French emphasizes that this typical investor is an average of everyone aiming to outperform the market — including the supposedly best and brightest who run hedge funds.

08 March 2008

When you are using more virtual memory than you have physical memory, the usual solution is to swap pages out to a hard disk.

What about compressing those pages, sticking them in a corner of physical memory, and decompressing them when they're needed again? This is what compcache does. It's a win for read times because zero latency + decompression time is still faster than hard disk latencies. And at a high level it makes sense because new computers typically have many processors but only one hard disk.

02 March 2008

I made pork vindaloo this past weekend, using a recipe out of The America's Test Kitchen Cookbook.

It was very tasty. Unlike the vindaloo I have had at Indian restaurants, it was not painfully spicy. It consisted of country style pork ribs, tomatoes, onions, spiciness to taste, and the secret ingredient, red wine vinegar, all stewed in a crock pot for about five hours.

Some people swear that it isn't vindaloo without pork, but the sauce was sufficiently tasty that I will try it with chicken or just vegetables next time.

MIT's very own Kiran Kedlaya is going to the American Crossword Puzzle Tournament. He practices on New York Times crosswords:

For a really good solver, Monday's puzzle would take about three minutes, while Friday and Saturday puzzles would take seven to 10 minutes, says Kedlaya. Sunday's puzzle, which is larger, could take eight to 15 minutes.

Enough said.

I prefer the Wall Street Journal's myself, although that may be because it's harder for me to get my hands on a NYT.

01 March 2008

If you've been in the general vicinity of me in the last six months, you have likely heard me raving about my new Thinkpad (I got an X61s last September). It's powerful, durable (I've dropped it on the ice once already), well supported by free software, and has great battery life. It's light enough that I don't think twice about taking it with me everywhere. But the thing that has impressed me the most has been the TrackPoint (the pointing device with many other names.)

I was somewhat apprehensive about buying a laptop without a touchpad, but after getting used to the TrackPoint I can't imagine going back. Touchpads are crude and error-prone input devices. They are easily confused if you let an extra finger or the side of your hand stray onto the surface. You have to constantly re-place your fingers to move or scroll long distances. Touchpads get grimy and crumby and acquire little dead zones. And, of course, touchpads are typically located many centimeters away from where you want your fingers to be while typing. So you have to move your wrists to switch between pointing and typing. It's practically uncivilized.

The TrackPoint is right in the middle of the keyboard, so you only have to move your index finger over the width of one key in order to use it. You can use it for both pointing and scrolling (just hold down the middle button and point; this works out of the box on Windows, and you can easily configure it under Linux as well). Just by pushing and holding in one direction you can move or scroll arbitrary distances. And the finger displacement needed to use the TrackPoint is on the order of millimeters, not centimeters.

The TrackPoint is a solid-state device which senses pointing via resistive strain gauges, and I have not had any reliability problems with it. Lenovo has developed some pretty sophisticated software which continually recalibrates the device so it doesn't drift.

When I heard that the scroll ball on Apple's Mighty Mouse (which is supposed to permit scrolling along two axes) acquires dust and grime really easily, I wondered if there was some more reliable two-axis pointing device you could put on top of a mouse.

Putting an optical sensor on top of the mouse might work, but I suspect that there wouldn't be enough feedback to make it feel natural, and you would also have to have a pretty fine optical sensor to figure out when your finger was (or was not) in contact with the thing.

But what about putting a TrackPoint on top? Is there a firm, I wondered, that was crazy enough to put a pointing stick on top of a mouse? As it turns out, Lenovo itself makes such a thing; it's called the ScrollPoint mouse.

From a quick Google search, you can apparently get one of these for around $25.

21 February 2008

Nine researchers at Princeton have demonstrated that DRAM retains its contents fairly accurately even after seconds or minutes without power (even longer when the chips are cooled with canned air cold gunk, or liquid nitrogen).

This means you cannot assume that secrets are safe when stored in memory: the conventional wisdom was that the OS controlled access to memory, and that circumventing that would require you to cut the power, which would wipe the contents of memory. However, it turns out that the contents of memory stick around for a while, at least long enough to let you boot into a malicious OS from which you can read the information.

The researchers demonstrate that disk-encryption products can be attacked in this way: cut the power, boot into another OS, grab the cryptographic keys out of memory, and use those to decrypt the disk.

09 February 2008

MVS LLC is developing a novel system for presenting directions to drivers. The system, called Virtual Cable, projects onto your windshield an image of what looks like an overhead cable over your route. Unlike the talking directions typical of modern satnav systems, this is silent, intuitive and unambiguous.

23andme will wend you a "spit kit" by mail. Within 6-8 weeks after you return it, they'll sequence your DNA at more than 500,000 loci of interest using an SNP array. Information at some of these loci can indicate susceptibility to certain diseases and conditions, like prostate cancer, sensitivity to alcohol, or lactose intolerance. Common differences in these loci can also help determine your ancestry.

You can later retrieve your profile results on the web, and read about how recent medical findings may affect you, learn how your genes relate to those of your relatives or others around the world.

I'd guess that that most users today are doing it for the novelty and trivia factors. This will probably change as these tests (and our knowledge of genetics) become even more sophisticated.

23andme's waiver asks you to acknowledge that "You may learn information about yourself that you do not anticipate." Indeed, one testimonial in a comment on their blog reads:

I handed out 23andme kits to my relatives at Christmas, and a few weeks later my wife found out that her "father" was not really her father. Needless to say, it turned out to be not such a great Christmas gift! But I love it anyway...

02 February 2008

The bhut jolokia pepper was declared the world's hottest pepper by the Guinness Book of World Records:

A panel of tasters used to rank chilies. Now a process called high performance liquid chromatography does all the work, with results given in Scoville Heat Units. The peppers yielded a reading of 1,041,427 SHUs, twice that of the California red savina pepper, the previous record-holder. An SHU is the amount of dilution needed before the chili is undetectable.

A publication of the Brooklyn Botanical Garden in New York described it this way: "When capsaicin comes into contact with the nerve endings in the tongue and mouth, pain messengers, called neurotransmitters, are sent to the brain in a panic. The brain, mistakenly perceiving that the body is in big trouble, responds by turning on the waterworks to douse the flames. The mouth salivates, the nose runs and the upper body breaks into a sweat. The heart beats faster and the natural painkiller endorphin is secreted. In other words, you get a buzz."

It's similar to a runner's high, says Bruce Bryant, a researcher for the Monell Chemical Senses Center in Philadelphia, which specializes in analyzing taste.

Just one year ago, everyone thought it was either not feasible or not lucrative to make an inexpensive subnotebook computer. The most popular subnotebook manufacturers were Sony and Fujitsu, whose products cost around $2000. Most casual users who are looking for a subnotebook are going to be hard-pressed to justify buying one of those now when they can get an Eee PC for $300. Asus pretty much came out of nowhere and is now proceeding to mop up this niche.

The Eee PC uses flash storage instead of a hard drive, which is a minus for capacity but a plus for reliability. This is a fine compromise since few people use a subnotebook as their primary computer anyway. In size and weight the Eee PC is pretty much up there with the best of them. It weighs less than a kilogram. It's the size of a paperback book. It boots up in 15 seconds. And it's hard to argue with $300. You can barely get a desktop computer for $300!

The Eee PC ships with a GNU/Linux-based operating system preinstalled. This is interesting for a couple of reasons:

At $300 (and Asus is aiming to hit $200), buying a Windows license, even at OEM prices, would be a huge chunk of the cost of the machine. It seems obvious now that the cheapest machines are where free software would appear pre-installed initially in mass-market computers.

Asus created its own operating system for this machine. This makes sense because the Eee PC has its own strengths and limitations when compared to a full-size notebook. Users are not going to use them for all the same things; however, historically, subnotebook manufacturers tried to dress up subnotebooks in the same manner as all their other notebooks. Since Asus is in control of the entire operating system and what ships with the computer, it also can ensure that the software works well with the hardware, which is still a worry for some adopters of GNU/Linux today (mostly with respect to graphics and wireless chipsets, many of which do not have free drivers). I think we'll see the quality of this integration (from all manufacturers) improve dramatically in the next couple of years as the flexibility of free software becomes more obvious.

29 January 2008

eHarmony [...] pioneered the don’t-try-this-yourself approach eight years ago by refusing to let its online customers browse for their own dates. It requires them to answer a 258-question personality test and then picks potential partners. The company estimates, based on a national Harris survey it commissioned, that its matchmaking was responsible for about 2 percent of the marriages in America last year, nearly 120 weddings a day.

[Academics] are skeptical, because the algorithms and the results have not been published for peer review. But they also realize that these online companies give scientists a remarkable opportunity to gather enormous amounts of data and test their theories in the field. EHarmony says more than 19 million people have filled out its questionnaire.

... [One] thing is already clear. People aren’t so good at picking their own mates online. Researchers who studied online dating found that the customers typically ended up going out with fewer than 1 percent of the people whose profiles they studied, and that those dates often ended up being huge letdowns.

The last bit is unsurprising. How much information could you get about a person from a blurb, and how much of that is likely to be be useful information?

27 January 2008

Exeter devotes an average of $63,500 annually to house and educate each of its 1,000 students. That is [...] well above even the $36,500 in tuition, room and board Exeter charges those paying full price.

Last year — fueled by gifts from wealthy alumni and its own successful investments — it crossed the $1 billion mark, up from just over $500 million in 2002.

26 January 2008

Scientists at the J. Craig Venter Institute in Maryland announced that they have synthesized the genome of a bacterium, Mycoplasma genitalium.

This is a symbolic milestone for DNA synthesis techniques because Mycoplasma genitalium is one of the simplest known living organisms (a little over 500,000 base pairs). The synthesized DNA is not capable of reproducing until scientists can synthesize a cell in which the DNA is viable.

It's believed that the techniques that the researchers used are already nearing their limits. E. coli bacteria were used to synthesize the DNA, but the bacteria could not produce DNA segments of more than a quarter of the length of what was needed. So yeast were used to stitch the pieces together to create the final result. Wired calls it "the end of the beginning for biological engineering": the first point where scalable and automatic DNA synthesis is becoming necessary. In electrical engineering terms, we need to move on from circuits wired by hand before we can make a PC.

Last week, I attended a talk in which Tom Knight described the next steps for synthetic organisms. Researchers are working on "refactoring" the code of simple organisms so that the functions of genes can be better understood. No computer scientist will be surprised that billions of years of evolution (with no code reviews, a huge space premium, and tight ship deadlines) has led to a bunch of ugly hacks.

22 January 2008

SmartWater is a fluid you can apply to valuables such as jewelry, electronics, and vehicles. Although invisible to the naked eye, it fluoresces under UV light, and its manufacturers claim that it is nearly impossible to completely remove. Each batch contains a unique signature of "micro-dots" which can be used to trace stolen property back to its owners.

Even though I had never heard of this, apparently it has enough of a reputation among thieves that displaying signs saying goods are tagged with SmartWater was a better theft deterrent than CCTV, burglar alarms, and security guards.

Amusingly, there is also a version of SmartWater intended to be thrown on bank robbers and other criminals to link them to a crime scene.

Campaign trolls popped up en masse in 2004 on Democratic presidential hopeful Howard Dean's Web site. Dean supporters batted them back with a "troll goal," donating money to the campaign's coffers each time they spotted an offending post. The supporters crowed about each sighting, eliminating the trolls' incentive to disrupt. [...]

Daily Kos has another tactic: the recipe. When a troll attempts to start a conversation at that site, loyalists post recipes instead of engaging them. With so many trolls, the recipes have proliferated -- enough so that Daily Kos compiled a 144-page "Trollhouse Cookbook," including crab bisque inspired by President Bush's second inauguration and "Liberal Elite Cranberry Glazed Brie."

However, in some cases I believe the cure to this problem has the potential to be worse than the disease. Purging posts that aren't libelous, etc. is a disservice to political debate.

"If you're on a site and you're just agreeing with each other all day, where's the argument?"

20 January 2008

Interesting article by an engineer who worked on dBASE, drawing parallels between that product and Windows Vista:

There were some brilliant people at Ashton-Tate, and I was fortunate to know many of them. When talking about dBASE, they were proud of their product, and it was the size of the customer base that was the de facto definition of why dBASE was a good product. This is part of the pattern. We are number one! Our product clearly must be the reason.

As I got to know people during that project, eventually there was more trust. Engineers at Ashton-Tate knew something was wrong. There was almost a sadness in discussions about how to fix it, as if they knew it was unfixable.

By 1989, dBASE's market share dropped to 43%. That's a 20% drop in just one year. When Microsoft Access came out in 1992, dBASE was dead. Crashed to the ground in no more than 4 years.

Compatibility. That's what killed them.

dBASE had to be upward compatible at any cost, even if it meant creating extremely bloated and arcane features to support such compatibility. Why? Because of the market. The market was all Ashton-Tate had.

[...] The flawed belief that compatibility will assure market share has been disproven time and time again.

What happened to dBASE was a lot more dramatic than what will happen to Windows (at least anytime soon), but Microsoft certainly realizes that it does have to change the way it develops Windows.

06 January 2008

#13: Wishful thinking. I am amazed at how many problems in software development boil down to wishful thinking. How many times have you heard statements like these:

"None of the team members really believed that they could complete the project according to the schedule they were given, but they thought that maybe if everyone worked hard, and nothing went wrong, and they got a few lucky breaks, they just might be able to pull it off."

"Our team hasn't done very much work to coordinate the interfaces among the different parts of the product, but we've all been in good communication about other things, and the interfaces are relatively simple, so it'll probably take only a day or two to shake out the bugs."

05 January 2008

On a clear day, visual cues let the pilot's brain correct for errors. But in the dark, a pilot who misreads the plane's instruments can end up in a death spiral. Between 1990 and 2004, 11 percent of US Air Force crashes — and almost a quarter of crashes at night — resulted from spatial disorientation. ...

Tom Schnell [Director of the Operator Performance Lab at the University of Iowa] showed me the the next-generation garment, the Spatial Orientation Enhancement System ... a mesh of hard-shell plastic, elastic, and Velcro that fit over my arms and torso, strung with vibrating elements called tactile stimulators, or tactors.

Flight became intuitive. When the plane tilted to the right, my right wrist started to vibrate — then the elbow, and then the shoulder as the bank sharpened. It was like my arm was getting deeper and deeper into something. To level off, I just moved the joystick until the buzzing stopped. I closed my eyes so I could ignore the screen.

02 January 2008

DNA is not like C source but more like byte-compiled code for a virtual machine called 'the nucleus'. It is very doubtful that there is a source to this byte compilation - what you see is all you get.

[The first C compiler was not written in C, obviously] but in a language that was available already: B. ... The same holds for the genome. To create a new 'binary' of a specimen, a living copy is required. The genome needs an elaborate toolchain in order to deliver a living thing. The code itself is impotent. This toolchain is commonly called 'your parents'.

You can see where some of his analogies are straining, but the article as a whole is still very enlightening.

Like the author, I'd also like to heartily recommend Matt Ridley's Genome and Richard Dawkins' The Selfish Gene.

Disclosure

I'm a software engineer at DNAnexus, Inc. This blog represents the opinion of myself and no one else.Unless specifically noted otherwise, I do not receive free review copies of books or other products mentioned here.